How Armor Works in Dota 2 – What You Need to Know

Armor plays a crucial role in Dota 2 gameplay, as it reduces the physical damage heroes take from attacks and abilities. Understanding how it works is vital for surviving against hard-hitting carries. In this guide, I’ll explain how armor works, how to increase it, and when to prioritize it over other defenses to make smarter item purchases.

What is Armor in Dota 2?

Armor is one of the most crucial defensive mechanics in Dota 2. It directly influences how much physical damage a hero takes during fights. Many new players might focus on increasing their health and magic resistance, but armor is just as important. 

In a nutshell, armor functions as a physical damage reducer. This means heroes become tankier against right-click hits, as the higher your armor, the less physical damage is applied to your hero. 

Unlike magic resistance, armor does not affect magical or pure damage – only physical. This means that a hero with extremely high armor can still take full damage from spells or abilities that deal magic and pure damage. 

How to Gain Armor

Every hero in Dota 2 starts with a certain amount of armor, which is referred to as “base armor.” A hero’s base armor depends on their primary attributes and design. 

Strength gives heroes health, Intelligence gives heroes mana, while Agility gives heroes armor. This means agility heroes often start with higher base armor, while heroes with other primary attributes generally have less. 

Base Armor Calculation

Base armor increases naturally through the Agility stat. Every point of Agility adds approximately 0.167 (⅙) armor. This means:

• Heroes that gain Agility points per level naturally scale in armor as the game progresses.
• Dota items that grant heroes Agility points, like Butterfly, Wraith Band, Yasha, or Dragon Lance, also indirectly boost the hero’s armor due to the stat bonuses. 

This is why new players fall under the misconception that Agility carries like Luna are squishy. Yes, she doesn’t have too many hit points, but her incredible Agility scaling allows her to have way more natural (base) armor than most heroes in the game. 

The Agility scaling means Luna is resistant to physical damage more than magic and/or pure damage. The same goes for most Agility carries. 

Bonus Armor

Aside from naturally scaling through Agility points and base armor, heroes can gain bonus armor through: 

• Items like Assault Cuirass, Shiva’s Guard, or Platemail, which grant heroes armor. 
• Talents that straight up grant armor bonuses. 
• Spells that temporarily grant heroes additional armor, such as Sven’s Warcry or Treant Protector’s Living Armor.
• Items that grant auras, such as Vladmir’s Offering and Assault Cuirass. 

Both base armor and bonus armor stack together, creating a total armor value that determines how much physical damage reduction your hero has. Base armor from stats is displayed in gray text, while bonus armor is displayed in green text. 

Armor and Damage Reduction

The relationship between armor and damage reduction gets a little confusing, as Dota 2 uses a diminishing returns formula. 

This formula means that, while each additional point of armor increases your survivability against physical damage, the effectiveness of each point gradually decreases. 

To put it into perspective, going from 0 to 10 armor reduces incoming physical damage by around 37%. However, going from 10 to 20 armor increases your reduction by only an additional 16%. 

Interactions with Armor

Now, let’s check out the most common armor-related interactions in the game to give you a better understanding of how it works and how you can make smarter decisions.

Armor Reduction

Armor reduction is a powerful mechanic that makes enemy heroes far more vulnerable to physical damage. It works by lowering the target’s armor value, leading them to take more damage from physical damage hits. 

Some of the most common sources of armor-reducing items include:

• Desolator: Heroes get an attack modifier when purchasing Desolator. Each attack applies a negative armor debuff on the enemy. 
• Assault Cuirass: The Assault Cuirass item doesn’t just give you and your teammates additional armor. The item’s aura also reduces the armor of nearby enemy heroes. 

Several abilities in the game also reduce armor:

• Slardar’s Corrosive Haze: When cast on a target, Slardar’s ability provides a massive single-target armor reduction. 
• Vengeful Spirit’s Wave of Terror: The Wave of Terror spell applies AoE armor reduction to all enemies it hits, allowing Vengeful Spirit to hit multiple heroes. 
• Tidehunter’s Gush: A regular Gush is a single-target spell that reduces armor while also slowing enemies. With an Aghanim’s Scepter upgrade, Gush becomes AoE. 

Teams or heroes that rely on right-click damage often stack armor reduction items to amplify their damage against enemy heroes. Reducing armor allows them to quickly burst down even the tankiest heroes. 

Armor Negation

Armor negation is a unique mechanic that bypasses armor values altogether, making it extremely dangerous against heroes with high armor. Unlike armor reduction, which lowers the armor number, armor negation literally treats the target’s armor as if it doesn’t exist. 

• Drow Ranger’s Marksmanship: Drow Ranger’s ultimate is a passive ability that negates an enemy hero’s base armor. This means all armor from the Agility stat is completely ignored, but bonus armor from items like Assault Cuirass isn’t. 
• Elder Titan’s Natural Order: Elder Titan’s passive ability removes base armor entirely within its aura range. Similar to Drow Ranger, this spell only negates base armor, not bonus armor. 

So, Drow Ranger and Elder Titan can be very threatening against high-armored lineups. However, they can only negate base armor. This means heroes like Dragon Knight and Tiny, who receive bonus armor from their spells, aren’t fully countered. Buying items that grant armor, such as Platemail and Solar Crest, also gives bonus armor, not base armor. 

When to Build Armor

Dota 2 isn’t just about dealing damage – it’s also about surviving the damage dealt by the enemy team. Armor becomes increasingly valuable when facing heroes or lineups that rely on high physical damage. Mostly, we’re talking about carry heroes.

Carries such as Phantom Assassin, Sven, and Templar Assassin dish out heavy physical damage because that’s simply how they were designed. If your heroes have low armor, they will shred through you – no questions asked. 

Assault Cuirass is arguably the best item to buy against heroes like these, and the best part is that only one hero on your team needs to buy it. This item not only boosts your own armor, but also reduces the enemy team’s armor, making it both defensive and offensive. 

Don’t Confuse Yourself with Magic-Damage Carries

Not all right-click carries rely solely on physical damage. Heroes like Juggernaut, Sniper, and Faceless Void often purchase items such as Maelstrom or Monkey King Bar, which add magic damage procs to their attacks.

While their base right-clicks still deal physical damage, a significant portion of their total DPS comes from these magical attack modifiers, which armor does not protect you from. Always pay close attention to the items an enemy carry builds before deciding whether armor or other forms of mitigation are the better defensive choice.